
Trigonal EuMg\(_2\) Bi\(_2\)  single crystals with room-temperature hexagonal lattice parameters \(a = 4.7724(3)\)  Å  and \(c = 7.8483(5)\)  Å were grown by a self-flux method with starting composition EuMg\(_4\) Bi\(_6\)  as reported earlier [1]}, [2]}. EuMg\(_2\) Sb\(_2\)  single crystals with room-temperature hexagonal lattice parameters \(a = b = 4.6861(3)\)  Å and \(c = 7.7231(5)\)  Å were also grown using self-flux with starting composition EuMg\(_4\) Sb\(_{16}\)  [3]}. The magnetization measurements were carried out using a Magnetic Properties Measurement System (MPMS, Quantum Design, Inc.) operating in the temperature range 1.8–300 K and with magnetic fields \(H\)  up to 5.5 T (1 T = 10\(^4\)  Oe). For measurements with the field applied in the \(ab\)  plane, the magnetic field was perpendicular to the [100] direction of the hexagonal unit cell as determined from Laue x-ray diffraction measurements, whereas in Ref. [1]} the field was applied in an arbitrary direction in the \(ab\)  plane.
